This invention generally relates to a mortise door locking device. More particularly, this invention relates to a mortise door locking device including a sensing mechanism for detecting when a door is in an unsecured position.
A mortise door locking device normally includes a main bolt and an auxiliary bolt that are both extended when the door is fully open. When the door is closed, the main bolt extends through a strike plate into a doorframe to hold the door securely, while the auxiliary bolt is pressed inward into the door by the strike plate. Currently known devices use sensors that determine whether the door is closed by checking the position of the auxiliary bolt. The sensor assumes that the door is closed and secure if the auxiliary bolt is retracted.
During normal door operation, this is usually true; however, there are cases where the auxiliary bolt is retracted sufficiently for the sensor to assume the door is closed and secure even though it is actually ajar (i.e., in an unsecure position). For example, the weather-stripping may keep the door from reliably closing because the latch bolt does not reach the strike plate hole, where it would extend and lock the door. However, because the sensor relies on the auxiliary bolt to determine the state of the door, the auxiliary bolt may indicate that the door is closed even though the main bolt may be retracted.
Accordingly, it is desirable to design and develop a door latch that monitors a position of both the main and auxiliary latches.